1. Field of the Invention
The present invention relates to a method for determining a transmission value for the security of transmission of motion between two components that transmit motion through frictional engagement. The invention also relates to apparatus for carrying out such a method.
2. Description of the Related Art
For convenience, fuel consumption, and environmental reasons, automated power trains are being used more often in motor vehicles. Such power trains contain, for example, a belt-driven conical-pulley transmission with a continuously variable transmission ratio. To ensure prolonged reliable operation of such a transmission, suitable contact pressure between the endless torque-transmitting means and the conical disks is important. Suitable contact pressure means, first, that the pressure ensures that the endless torque-transmitting means does not slip, and, second, that the contact pressure is not unnecessarily high, so that it does not produce any unacceptable loads on parts or impair the operating efficiency as a result of the high hydraulic pressure that must be provided. To appropriately control or regulate the contact pressure, precise knowledge of the slippage condition or of the security of transmission between the conical disks of the belt-driven conical-pulley transmission and the endless torque-transmitting means is necessary. Direct measurement of that slippage is complicated and expensive, because in addition to the rotational speeds of the pulleys and the speed of the endless torque-transmitting means, it is also necessary to know the exact effective radii at which the frictional engagement between the endless torque-transmitting means and the conical surfaces of the pulleys occurs.
An object of the present invention is to provide a simply-executed method for determining a transmission value for the security of motion transmission in, for example, a belt-driven conical-pulley transmission. The invention also has as an object to provide apparatus for carrying out such a method.